Renal Effects of Sulfated Polysaccharides from the Seaweed Gracilaria cornea

Sulfated polysaccharides (SPs) are abundant in seaweed and have several industrial and biomedical applications, but their renal effects remain unclear. This study evaluated the effects of total sulfated polysaccharides (TSPs) from Gracilaria cornea using an isolated rat kidney perfusion model. TSP at 3 µg/mL increased perfusion pressure and renal vascular resistance at 90-120 min, while 4.5 µg/mL induced earlier and more pronounced changes (from 60 min). Urinary flow decreased at 1 µg/mL (90 min) but increased at 4.5 µg/mL (90-120 min). Sodium transport was reduced at all concentrations, whereas potassium and chloride transport remained unchanged. Histological analysis revealed protein deposits in tubules and urinary space, indicating tubular injury. In vitro, TSP reduced MDCK cell viability in a concentration-dependent manner and induced apoptosis, with some cells progressing to secondary necrosis. In conclusion, TSP altered renal physiology and morphology and triggered apoptotic pathways in renal cells, highlighting the need for further mechanistic and translational studies.